For a Madrileno it is the ultimate grudge match, but when you have also triumphed over them as manager of Valencia, then playing Barcelona in the Champions' League's last 16 takes on another dimension altogether.
Rafael Benitez said yesterday that his Liverpool team did not fear the European champions and relished their role as underdogs in the most engrossing tie of the next round for the English participants.
"They [Barcelona] think it's a good draw and that they are better than us," Benitez said. "They will have a lot of confidence, but you will see a big difference in our players at this level."
Liverpool's Spanish manager also said that the many messages and calls he had already received from friends in Barcelona suggested a degree of over-confidence in the reigning champions.
Benitez may say he is bullish about his side's prospects against Ronaldinho, Lionel Messi, Deco and Samuel Eto'o, when he returns to fitness, but he is entitled to feel like the unlucky one when he looks at who the other English teams have drawn. Manchester United have arguably the round's easiest opponents, Lille, to whom they lost last season in Paris. Also in February, Arsenal face PSV Eindhoven while Jose Mourinho goes back to Porto with Chelsea.
From the British sides, only Celtic, who face Milan, share Liverpool's status as underdogs. "The draw was not kind and not unkind," Arsène Wenger said, although it was certainly unkindest to Liverpool.
There have been some of the greatest European nights in English football at Anfield but few as demoralising as the last time Barcelona visited and inflicted a 3-1 defeat on Gérard Houllier's side in the group stages of the competition in November 2001. Having beaten them in the Uefa Cup the previous year, Houllier was then famously accused of "betraying football" by the Spanish media when he played for a goalless draw in the Nou Camp the following March.
No such worries for Benitez, who talked yesterday about his own experience of winning at the Nou Camp with Valencia who, he said, were the Catalan club's bogey team for years. "There is a big difference between this draw and the knockout stage last season and I think it suits us," Benitez said. "Everyone said Benfica would be easy; now they are saying Barcelona will be impossible. Perfect. It was the same against Juventus, Chelsea and Milan two years ago. We have nothing to lose so we can focus only on our game and just play our football.
"I saw on the television before the draw so many people in Barcelona hoping to get Liverpool. I didn't see the draw itself because we were training, but when I came back off the pitch my phone was full of messages and missed calls from people in Barcelona. They all think it's a good draw and that they are better than us. They will have a lot of confidence, but you will see a big difference in our players at this level."
For Barcelona's pioneering president Joan Laporta, the draw will also allow him to fulfil a long-held ambition to trace the history of Liverpool's other famous cultural export. "It will be a great privilege for me to take in some of Liverpool's musical history," he said. "I can't wait to go to The Cavern and other wonderful places associated with The Beatles. This is the game that I was hoping for."
It will not be the first time that Mourinho has gone back to Porto - he returned to the club he guided to the 2004 European Cup in his first season at Chelsea - but he is likely to get a better reception at the Estadio do Dragao this time around. While the immediate shock of his departure had not yet passed in the autumn of 2004, he is now recognised as one of the greats at a club who have little expectation of progressing past this round.
"It could have been worse," Arjen Robben said. "The likes of Internazionale and Real Madrid were the teams, if not to avoid, but the toughest out there. It's not an easy draw. All the teams are difficult. We look at it as a normal game. For the Portuguese [at Chelsea] it's a special game and it will give them an extra bit of pleasure if we beat them. But we have to look at it as a normal game and just go through."
Mourinho took four key backroom staff with him, not to mention Ricardo Carvalho and Paulo Ferreira, when he left Porto for Chelsea in the summer of 2004. Porto regained the title last season and look set to retain it this time too, and they ran Arsenal close in the final game of the group stages. Their best player however, the Brazilian striker Anderson, 18, is injured and will miss the games against Chelsea.
"We had a bad experience last year but this is a different United team," Sir Alex Ferguson said yesterday as he recalled the shock of defeat to knockout round opponents Lille in the group stages last year. When they lost to them in Paris in November last year, United were still mired in the controversy surrounding the withdrawal of Roy Keane's controversial and still-unseen MUTV interview, which began the process that ended with his departure from the club.
Lille played their games at the Stade de France last year; this season they are in the more atmospheric 41,000-capacity Stade Felix-Bollaert in Lens. United have not won a Champions' League knockout match away from home since a trip to Deportivo La Coruña in 2002, although Ferguson said he was simply glad they had made it this far.
"In a way, it didn't really matter who we got. The important thing is that we are there," he said. "It is an emerging team, which is getting better all the time. We know it will be a difficult tie but we have improved so much from last season. Our European record over the last few years has not done us any good. This club has had some great European challenges over the years and some terrific journeys. We have played in semi-finals and quarter-finals and a final."
Lille are managed by Claude Puel, who was Wenger's assistant at Monaco, and the Arsenal manager warned United that the French side would be no "easy target". "Their manager is one of my former players, and he is a very resilient guy. He will get his team to fight."
As for PSV, Wenger said: "They dominate Dutch football and every year now they are in the last 16, quarter-final, semi-final even of the Champions' League against Milan. So it is a tough draw.
"Our results have been good, and we have a little advantage with our first game over there," Wenger continued. "It is like a game of 180 minutes, where the first 90 decide the rest.
"You have five British teams in the last 16 - that would not have happened 10 years ago and that means our game has moved on."
Champions collide: European Cup winners Liverpool and Barcelona renew hostilities
Liverpool may not be as fearful of Barcelona as anticipated, as in three matches at the Nou Camp they have yet to concede a goal. On their last visit, in March 2002, an uncompromising defensive display helped them to reach the Champions' League knockout stages.
Yesterday's pairing will also rekindle fond memories of the 1976 Uefa Cup semi-final, second leg. Liverpool went into the game leading a Barcelona team boasting Johan Cruyff and Johan Neeskens 1-0 after John Toshack had scored at the Nou Camp.
The return leg was watched by 55,104, still the largest attendance for a European match at Anfield. Phil Thompson doubled Liverpool's advantage when he scrambled in a close-range goal in the 50th minute but Carles Rexach soon equalised. In a tense finish Liverpool held on to progress 2-1 on aggregate.
Bob Paisley's team went on to defeat Club Bruges 4-3 on aggregate in the final.
On the road to Athens: Draw for the last 16
Celtic v Milan
Form: LWWLWL - WWWDWWLL
Key clash: Shunsuke Nakamura v Kaka
Last meetings: 2004-05: Celtic 0 Milan 0, Milan 3 Celtic 1
Killer fact: Milan's Kaka has had the most shots on goal this Champions' League season
Lille v Manchester United
Form: WWDDWLDW - WWWLLW
Key clash: Gregory Tafforeau v Cristiano Ronaldo
Last meetings: 2005-06: Lille 1 Manchester United 0, Manchester United 0 Lille 0
Killer fact: Manchester United have beaten
Lille once in four attempts, David Beckham
scoring a last-minute winner five seasons ago
PSV Eindhoven v Arsenal
Form: DWWWLL - WWWWLDWD
Key clash: Alex v Thierry Henry
Last meetings: 2004-05: Arsenal 1 PSV 0, PSV 1 Arsenal 1
Killer fact: When Arsenal won 4-0 in Eindhoven in 2002 Gilberto Silva scored after 20 seconds
Real Madrid v Bayern Munich
Form: LWWWDD - WWWDDD
Key clash: Fabio Cannavaro v Roy Makaay
Last meetings: 2004-05: Bayern Munich 1 Real Madrid 1, Real Madrid 1 Bayern Munich 0
Killer fact: Bayern Munich have not kept a clean sheet in any competition since October.
Above ties to be played: Feb 20 and Mar 7
Barcelona v Liverpool
Form: WDLDWW - WDDWWWWL
Key clash: Deco v Steven Gerrard
Last meetings: 2001-02: Barcelona 0 Liverpool 0, Liverpool 1 Barcelona 3
Killer fact: Liverpool have three ex-Barça players; Boudewijn Zenden, Luis Garcia and Pepe Reina, and five others with La Liga experience
Internazionale v Valencia
Form: LLWWWD - LWWWWDWL
Key clash: Marco Materazzi v David Villa
Last meetings: 2004-05: Internazionale 0 Valencia 0, Valencia 1 Internazionale 5
Killer fact: Internazionale have had three players sent off this campaign, Valencia none
Porto v Chelsea
Form: DLWWWD - WWWDLW
Key clash: Ricardo Quaresma v Ashley Cole
Last meetings: 2004-05: Chelsea 3 Porto 1, Porto 2 Chelsea 1
Killer fact: As well as manager Jose Mourinho, Chelsea players Hilario, Ricardo Carvalho and Paulo Ferreira were also at Porto
Roma v Lyon
Form: WLWDLW - WWWWDD
Key clash: Philippe Mexes v John Carew
Last meetings: They have never met
Killer fact: Lyon have lost once in 24 European and domestic games this season, at Rennes in the league
Above ties to be played: Feb 21 and Mar 6